Pin-tumbler lock



PIN-TUMBLER LOCK Filed 21. 1955 Z T R A W H c S E M 0 R E J PIN-TUMBLER LOCK Jerome Schwartz, Philadelphia, Pa., assignor to Taylor Lock Company, Philadelphia, Pa., a corporation of Pennsylvania Application August 21, 1953, Serial No. 375,745

3 Claims. (Cl. 70-364) This invention relates to an improved pin-tumbler lock having a sleeve embracing the rotatable plug and a pair of plates loosely and removably positioned on the sleeve, the plates cooperating to form a series of bores or chambers for receiving the pin-tumblers and spring followers which are operated by a key to selectively lock and unlock the rotatable plug. By making the cooperating plates removable from the sleeve, instead of integral therewith, considerable savings in time, effort and expense are effected in assembling the various parts of the lock.

A further important object of the invention is to provide a means associated with a pin-tumbler lock which serves to improve the floating action of the pin-tumblers and spring followers normally associated with the lock.

A further object of the invention is to provide a simple, inexpensive, dependable pin-tumbler lock which can be made of low-grade materials, such as zinc, and still retain the qualities of a lock made of a high-grade material such as brass.

And yet another object of the invention is to provide a pin-tumbler lock which is capable of being constructed in such a manner that the same metal is used for the movable parts and those which contact said movable parts While the lock body itself is made of a different and less expensive metal. This construction not only reduces the fabricating costs of the lock but also minimizes electrolytic corrosion which normally results from moving contact of unlike metals, particularly when exposed to adverse weather conditions.

These and other objects of the invention will become more apparent as the following description proceeds in conjunction with the accompanying drawings, wherein:

Figure 1 is a longitudinal sectional view through a pinturnoler lock mechanism incorporating the present invention, the pin-tumblers and spring followers being shown in elevation;

Figure 2 is a sectional view taken on the line 2-2 of Figure 1 with the pin-tumblers and spring followers removed; and

Figure 3 is a group perspective view of the split sleeve and the cooperating removable plates associated therewith.

Specific reference will now be made to the drawings wherein similar reference characters are used for corresponding elements throughout.

The present invention has been designed for assembly in a conventional pin-tumbler lock which comprises a lock body or main casing which is cast of any desired metal, preferably Zinc. Said lock body or main casing includes a face plate 12 and a longitudinally extending cylindrical bore 14 which is communicative with an upper reduced longitudinal slot 16. A cover plate 18 is secured on the upper open end of the reduced portion or slot 16 of the lock body.

Rotatable in the bore 14 is a plug 20 preferably fabricated of brass which is provided with a series of axially spaced bores 22 and a key entrance slot 24. Slidably received in the bores 22 are pin-tumblers 26, which also extend into the slot 16. Associated with each pin-tumbler States Patent 2,755,656 Patented July 24, 1956 is a spring 28 which is interposed between the cover plate 18 and the upper end of the pin tumbler, as shown clearly in Figure 1. The pin-tumblers and spring-followers are also preferably fabricated of brass.

The present invention comprises a split sleeve 30 which loosely embraces the rotatable plug 20. The split portion 32 of the sleeve 36 opens into the reduced portion or slot to of the lock body as shown clearly in Figure 2. Removably received in the reduced portion or slot 16 of the lock body is a pair of cooperating plates 34 and 36. These plates are preferably fluted to provide alternate bulged and indented portions 38 and 4%) which, when assembled in the lock, cooperate with each other to form pin-tumbler and spring follower chambers 42, which are substantially perpendicular to the axis of rotation of the plug 2%. The split sleeve and plates are also preferably fabricated of brass.

It will be noted that the fluted plates 34 and 36 are separable from the split sleeve 30 and are provided with terminal cars 44 to permit their suspension upon suitable shoulders provided in the lock body at the upper end of the reduced portion or slot 16 thereof.

Thus it will be seen that the split sleeve and cooperating fluted plates serve as a guide means for the rotatable plug, the pin-tumblers, and the spring followers.

By making the fluted plates 34 and 36 separable from the split sleeve 39, substantial economy is effected in the assembly of the split sleeve and plates in the lock body. In addition, since the movable parts of the lock and those which come in contact with them, namely, the rotatable plug, pin-tumblers, spring followers, split sleeve and plates, are fabricated of the same metal such as brass, electrolytic corrosion will be substantially reduced even though the lock body itself may be made of a less expensive and different metal, such as zinc.

Moreover, the separability of the fluted plates from the split sleeve, and their relatively loose suspension in the lock body, improves the floating mechanism of the pin tumblers. This is accomplished by the fact that the upper edges of the fluted plates are normally spaced as at 46 a short distance below the inner face of the cover plate 18. The opposite ends of the fluted plates are also normally spaced as at 48 a slight distance from the opposite ends of the lock body. Moreover, since the indented portions 40 of the fluted plates do not abut each other to form the chambers 42 for receiving the pin-tumblers and spring followers, a slight amount of side play is provided in the fluted plates.

In short, a slight amount of side, end, and vertical play results from the assembly of the removable fluted plates in the manner described hereabove so that they are capable of limited floating action. Thus, if one or more of the tumblers should bind against the inner walls of the chambers 42 of the fluted plates, the latter will give and permit free sliding movement of the pin-tumblers. This action would not be possible in a structure in which the fluted plates would be rigidly or integrally connected to the split sleeve.

While the preferred embodiment of the invention has been shown and described hereabove, it will be understood that minor variations may be made by skilled artisans without departing from the spirit of the invention and the scope of the appended claims.

I claim:

1. In a pin-tumbler lock having a lock body including a cylindrical bore and a reduced axially extending slot above and communicating with the bore, a rotatable plug in said bore and a series of pin-tumblers and spring followers arranged for cooperation with the plug to lock and unlock the same; a guide for said plug, pin-tumblers and followers which comprises an axially split sleeve loosely embracing said plug and a pair of fluted plates loosely and removably suspended in said lock body over said sleeve adjacent the opposite longitudinal edges of said split portion, said fluted plates cooperating to form a series of axially spaced bores substantiallyperpendicular to the axis of the plug and adapted to receive said pin tumblers and spring followers.

2. In a pin-tumbler lock including a lock body having a cylindrical bore and a reduced axially extending slot above and communicating with the bore, a rotatable plug in said bore and a series of pin-tumblers and spring followers arranged for cooperation with the plug to lock and unlock the same; a means to improve the floating action of the pin-tumblers comprising an axially split sleeve loosely embracing said plug and a pair of fluted plates removably suspended over said sleeve on both sides of the split portion and cooperating to form a series of axially spaced bores substantially perpendicular to the axis of the plug and adapted to receive said pin-tumblers and spring followers, said fluted plates being capable of slight side, end and vertical play.

3. In a pin-tumbler lock having a lock body including a cylindrical bore and a reduced axially extending slot above and communicating with the bore, a rotatable plug 4 in said bore and a series of pin-tumblers and spring followers arranged for cooperation with the plug to lock and unlock the same; a guide for said plug, pin-tumblers and followers which comprises an axially split sleeve loosely embracing said plug, shoulders carried by said lock body and extending into the reduced slot portion thereof, and a pair of fluted plates including ears engaging said shoulders whereby said plates are removably suspended in said slot above said sleeve and on both sides of the split portion thereof, said plates cooperating to form a series of axially spaced bores substantially perpendicular to the axis of said plug and adapted to receive said pintumblers and spring followers.

References Cited in the file of this patent UNITED STATES PATENTS 1,003,957 Voight Sept. 19, 1911 1,020,874 Augenbaum Mar. 19, 1912 1,338,053 Voight Apr. 27, 1920 1,431,735 Freysinger Oct. 10, 1922 1,433,361 Freysinger Oct. 24, 1922 1,656,854 Best Jan. 17, 1928 

